French is definitely prioritised in the private sector. My kids' prep dropped Greek a few years ago and Latin feels like an after thought, but French they do from Y1 (age 5).
The problem state education has is that the gold standard is a C in Maths GCSE, another in English, and once you've achieved those, the 5 A*-C is guaranteed.
So comps spend a huge amount of effort on boosting kids up from D to C in Maths, working on English, because if they can get up from a shitty 45% 5 A*-C at GCSE to something in the 60%+ or 70%+ range, then they will start to become a first choice school sought out by parents who care about their kids' education.
Maybe an interest in History and Geography can follow alongside the naice kids their improved results attracted, but I suspect it's more like:
Step 1: - work very hard to pass Maths + English GCSE
Step 2: ????
Step 3: Profit!
When you are paying for an education, the school is free to market itself on any aspect of its education, but state schools, aside from a few grammar schools, have little to go on beyond a league table position entirely determined by the number of children achieving a C in Maths and English at GCSE.